Wireless network operators have recently begun to track and deliver services to pre-defined groups of network subscriber mobile stations, such as cell phones and pagers, located within respective network coverage areas. This feature, known generally as location-based grouping, has numerous potential applications. For example, location-based grouping can enable a store owner subscriber to target and send advertising messages to network subscriber mobile stations located near the store, a company to track its service fleet and therefore provide faster and more cost effective customer service by enabling it to identify the service person closest to a customer location, or an individual to be notified if and when friends subscribing to the service are in a pre-defined coverage area location.
While the above types of applications are possible given current network operator capabilities, the applications are limited in accuracy due to the limited granularity offered by the network coverage areas. Specifically, the accuracy of the above-mentioned types of location-based grouping is limited by the size of the coverage areas defined by network transmitters. Although multiple transmitters may be used to define a particular service provider coverage area, the smallest zone that can be defined is that which the coverage area of a single transmitter can define. In addition, if members of a particular group are located across a wide area, contacting members of the particular group within a particular area may be difficult unless GPS location information is collected first before members closest to the particular area of interest can be identified.